1. Field of the Invention
The present invention relates to a piezoelectric component and a method for manufacturing the piezoelectric component.
2. Discussion of Background
Piezoelectric components have been widely employed in various types of electronic devices such as filters, resonators or oscillators in the prior art. A basic requirement that must be fulfilled by a piezoelectric component is that, since desired characteristics are achieved by utilizing the resonance characteristics, the degree of accuracy of its resonance frequency be high.
The following three methods are well known as means for achieving desired resonance characteristics by adjusting the resonance frequency of a piezoelectric component. In the first method, the thickness of the piezoelectric substrate is adjusted through polishing. In the second method, the thickness of the electrode is adjusted and in the third method, the desired resonance characteristics are achieved through the adjustment of the quantity of resin deposited onto the resonating part.
However, the first method poses problems in that it is difficult to perform polishing at the accuracy required for adjusting the resonance frequency and in that inconsistency occurs in the resonance frequency. The second method requires a great length of time and a great deal of work and, furthermore, it does not achieve good reproducibility. The third method presents a problem in that it is difficult to finely adjust the quantity of resin to be deposited onto the resonating part.
An improvement on the third method is disclosed in, for instance, Japanese Unexamined Patent Publication No. 160121/1981. This publication discloses a method whereby the resonance frequency of a piezoelectric substrate to which a mass substance is added in advance is measured, a correct quantity of the mass substance is removed by radiating a laser beam which is controlled in correspondence to the degree of deviation of the resonance frequency relative to the frequency setting on the mass substance added to the piezoelectric substrate to adjust the resonance frequency to the frequency setting.
However, the publication does not refer to specifically how the mass substance should be processed or what type of laser beam should be employed. Consequently, the method disclosed in the publication above is not sufficient to provide a piezoelectric component with a high degree of accuracy in the resonance frequency and a high Q value for its resonance characteristics.